§ 14-455. Damaging computers, computer systems, computer networks, and resources(a) It is unlawful to willfully and without authorization alter, damage, or destroy a computer, computer system, computer network, or any part thereof. A violation of this subsection is a Class G felony if the damage caused by the alteration, damage, or destruction is more than one thousand dollars ($1,000). Any other violation of this subsection is a Class 1 misdemeanor.

(b) This section applies to alteration, damage, or destruction effectuated by introducing, directly or indirectly, a computer program (including a self-replicating or a self-propagating computer program) into a computer, computer system, or computer network.

§ 14-456. Denial of computer services to an authorized user(a) Any person who willfully and without authorization denies or causes the denial of computer, computer system, or computer network services to an authorized user of the computer, computer system, or computer network services is guilty of a Class 1 misdemeanor.

(b) This section also applies to denial of services effectuated by introducing, directly or indirectly, a computer program (including a self-replicating or a self-propagating computer program) into a computer, computer system, or computer network.

§ 14-457. Extortion Any person who verbally or by a written or printed communication, maliciously threatens to commit an act described in G.S. 14-455 with the intent to extort money or any pecuniary advantage, or with the intent to compel any person to do or refrain from doing any act against his will, is guilty of a Class H felony.

Here's what our lawyer tells us about cyber crimes at a federal level...

The main federal computer crime statute is 18 U.S.C. Section 1030. It prohibits, among other things, "knowingly caus[ing] the transmission of a program, information, code, or command, and as a result of such conduct, intentionally caus[ing] damage without authorization, to a protected computer" Web servers in interstate commerce are within the definition of "protected computer", and (to my recollection) service down-time is "damage" even if the computer is not physically damaged.

There are common law civil claims that could be brought against a hacker, such as trespass to chattels and interference with contract.

The threat to take down your site is a serious matter on its face. I would suggest you ask for the cybercrimes unit at the branch office of the FBI.